Field of the Invention
The present invention relates to a paper cutting apparatus and a printing apparatus.
Description of the Related Art
A printing apparatus (such as a printer) for printing images on rolled paper, for example, has been known in the past. With a printing apparatus that prints on rolled paper, a cutter mechanism is generally provided that automatically cuts the rolled paper every time the printing of an image is finished. There are many different types of cutter mechanism, depending on how it is configured, such as a guillotine type that thrusts a blade into a gap, or a scissors type that crosses two blades and cuts from the end of the paper. Regardless of the type, the cutting of the paper is carried out by moving one or more blades.
Even though a cutter mechanism may operate without a problem during normal operation, if the paper should jam, or if a foreign substance should become lodged in the cutter mechanism, the blade or blades may not be able to work properly, resulting in a locked state. To deal with this, a technique has been disclosed in Japanese Patent Laid-Open No. 05-337876 in which the motor is reversed and the blade pulled back in the event of a locked state.
In general, the above-mentioned locked state occurs most often when a foreign substance becomes lodged between the cutter mechanism and the end of the paper opening of the apparatus main body. If a foreign substance becomes lodged during the cutting of paper, however, a state in which the load gradually builds up will usually continue for a time, with lock-up not occurring right away.
If current is used to detect lock-up, since the load varies with the type of paper, there will be a large change in the current during paper cutting. Accordingly, there is the possibility that mis-detection will occur.
If, for example, lock-up is detected during paper cutting, the printing apparatus reverses the motor and moves the cutter mechanism to its home position, etc. In this case, the paper ends up being cut only part of the way. This partially cut paper will tear at the partial cut line under the weight of the paper, so in a worst case scenario, the printed image portion ends up being ripped.